Operating Manual
Operating Manual 832 & 832M1, Rev B
www.te.com
October 20, 2015
6 of 8
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Frequently Asked Questions
Question:
The datasheet shows the operating temperature from -40
C to +125
C. -40
C is not low
enough; we need beyond -55
C. What is your plan of meeting this requirement?
Response
: We tested the bias at -55C. Test result of 832-0500 DC bias change with temperature is
shown below, DC Bias changes about 0.5% at -55ºC compared to 25ºC:
25ºC
-55ºC
X
1.7423 V
1.7535 V
Y
1.7412 V
1.7477 V
Z
1.7928 V
1.8035 V
Total current supply is 4.1uA at -55ºC which is still within specification. Model 832M1 has no problem
working down at -55ºC
Question:
Do you happen to have any more detail for the assembling of this part to a board? Our board
assembly department is a little concerned about manually soldering this part. It says on your data sheet
that the accelerometer can’t go through solder reflow at high temperature and that manual soldering is
recommended. I was hoping for some more clarification on this statement.
Response:
The reason for the caution is the potential risk of sensitivity shift in the output after reflow
soldering. The units will survive the reflow soldering process. We caution against this process since we
have seen a 1-2% sensitivity drop after reflow soldering. For our reflow profile we have a peak
temperature of +250
C since we use non-leaded solder for RoHS compliance. A lower reflow profile may
result in negligible sensitivity shift. If you can use leaded solder such Sn63 or Sn62 (183°C and 179°C
eutectic respectively) then the peak reflow temp should not have to 210
C (60sec max). This
should then allow reflow soldering.
Question:
We generally conformal coat our circuit boards to protect the circuitry, would there be any
concern with conformal coating?
Response:
No concerns with conformal coating. The seismic mass system and electronics are all
hermetically sealed under the cover.
Question:
Can we bake the board after coating?
Response:
Yes. There will be no problem with an over-night bake at +200
F on the model 832M1. We
bake the units for 24hours at +250
F during manufacture.
